Gaze tracking variations using selective illumination

ABSTRACT

Aspects of the present disclosure relate to eye tracking systems and methods which track eyes by illuminating the eyes using a light source and detecting the eye illuminations using a sensor. Implementations of the present disclosure may utilize wide angle lighting via a plurality of individual light sources which are each oriented in different orientations. A wide area may be illuminated by the different light sources, and these light sources may be selectively turned on and off based on a current location of a user.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.15/713,466, filed Sep. 22, 2017, the entire contents of which areincorporated herein by reference. U.S. patent application Ser. No.15/713,466 is a continuation of U.S. patent application Ser. No.14/493,738, filed Sep. 23, 2014, the entire disclosures of which areincorporated herein by reference. U.S. patent application Ser. No.14/493,738 claims the priority benefit of U.S. provisional patentapplication No. 61/881,660 filed Sep. 24, 2013, the entire disclosuresof which are incorporated herein by reference.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No.14/493,723 (now U.S. Pat. No. 9,468,373), filed Sep. 23, 2014, theentire contents of which are herein incorporated by reference.

This application is related to commonly-assigned, co-pending U.S. patentapplication Ser. No. 14/493,766 (now U.S. Pat. No. 9,480,397), filedSep. 23, 2014, the entire contents of which are herein incorporated byreference.

FIELD

The present disclosure relates to eye gaze tracking. In particular,aspects of the present disclosure relate to light sources for opticaleye gaze tracking systems.

BACKGROUND

Eye gaze tracking has use in a wide range of applications, includingmedical research, automobile technology, computer entertainment andvideo game programs, control input devices, augmented reality glasses,and more.

Some known eye gaze tracking techniques involve illuminating the eyes byemitting light from one or more light sources and detecting reflectionsof the emitted light off of the eyes with a sensor. Typically, this isaccomplished using invisible light sources in the infrared range andcapturing image data (e.g., images or video) of the illuminated eyeswith an infrared sensitive camera. Image processing algorithms are thenused to analyze the image data to determine eye gaze direction.

Generally, eye tracking image analysis takes advantage ofcharacteristics distinctive to how light is reflected off of the eyes todetermine eye gaze direction from the image. For example, the image maybe analyzed to identify eye location based on corneal reflections in theimage data, and the image may be further analyzed to determine gazedirection based on a relative location of the pupils in the image.

Two common gaze tracking techniques for determining eye gaze directionbased on pupil location are known as Bright Pupil tracking and DarkPupil tracking. Bright Pupil tracking involves illumination of the eyeswith a light source that is substantially in line with the optical axisof the camera, causing the emitted light to be reflected off of theretina and back to the camera through the pupil. The pupil presents inthe image as an identifiable bright spot at the location of the pupil,similar to the red eye effect which occurs in images during conventionalflash photography. Dark Pupil tracking involves illumination with alight source that is substantially off line from the optical axis of thecamera, causing light directed through the pupil to be reflected awayfrom the optical axis of the camera, resulting in an identifiable darkspot in the image at the location of the pupil.

In order to effectively determine the desired eye gaze characteristics(e.g., eye position, gaze direction, and the like), these trackingtechniques generally rely on the tracking system's ability toeffectively illuminate the user's eyes with the light source andeffectively detect the corresponding reflections of the emitted lightoff of these eyes. However, geometric parameters such as the location ofthe user with respect to the tracking system sensor and with respect tothe light sources of the tracking system can be highly variable,changing with different system setups and even different instances ofuse of the same tracking system setup.

It would be desirable to have an eye tracking system capable ofilluminating eyes and capturing corresponding eye illuminations in amanner that accounts a variety of different geometric parameters.Unfortunately, there is no way to efficiently do so using traditionaltechniques. It is within this context that aspects of the presentdisclosure arise.

SUMMARY

An implementation of the present disclosure may include a methodcomprising: emitting light from an eye tracking device, wherein saidemitting the light includes initially emitting the light from aplurality of light sources of the eye tracking device, each said lightsource being oriented to emit light at a different angle; detecting anarea illuminated by the light with a sensor of the eye tracking device;identifying one or more of the light sources as contributing lightsources from analysis of data gathered from said detecting the area,said identifying the light sources as the contributing light sourcesbeing based on a determination that the contributing light sourcesilluminate one or more eyes; and turning off the light sources notidentified as the contributing light sources, wherein said emitting thelight further includes, after said turning off the light sources,emitting the light from the contributing light sources, and wherein saiddetecting the area includes, after said turning off the light sources,detecting an area illuminated by the light from the contributing lightsources.

Another implementation of the present disclosure may include a systemcomprising: an eye tracking device having a sensor and a plurality oflight sources, each said light source being oriented to emit light at adifferent angle; and a computing device, wherein the system isconfigured to perform a method, the method comprising: emitting lightfrom the eye tracking device, wherein said emitting the light includesinitially emitting the light from the plurality of light sources;detecting an area illuminated by the light with the sensor; identifying,with the computing device, one or more of the light sources ascontributing light sources from analysis of data gathered from saiddetecting the area, said identifying the light sources as thecontributing light sources being based on a determination that thecontributing light sources illuminate one or more eyes; and turning offthe light sources not identified as the contributing light sources,wherein said emitting the light further includes, after said turning offthe light sources, emitting the light from the contributing lightsources, and wherein said detecting the area includes, after saidturning off the light sources, detecting an area illuminated by thelight from the contributing light sources.

A non-transitory computer readable medium having processor-executableinstructions embodied therein, wherein execution of the instructions bya processor causes the processor to perform a method, the methodcomprising: emitting light from an eye tracking device, wherein saidemitting the light includes initially emitting the light from aplurality of light sources of the eye tracking device, each said lightsource being oriented to emit light at a different angle; detecting anarea illuminated by the light with a sensor of the eye tracking device;identifying one or more of the light sources as contributing lightsources from analysis of data gathered from said detecting the area,said identifying the light sources as the contributing light sourcesbeing based on a determination that the contributing light sourcesilluminate one or more eyes; and turning off the light sources notidentified as the contributing light sources, wherein said emitting thelight further includes, after said turning off the light sources,emitting the light from the contributing light sources, and wherein saiddetecting the area includes, after said turning off the light sources,detecting an area illuminated by the light from the contributing lightsources.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present disclosure can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 is a schematic diagram depicting an example eye tracking devicein accordance with various aspects of the present disclosure.

FIGS. 2A-2D is a process flow diagram depicting and example a method ofeye tracking in accordance with various aspects of the presentdisclosure.

FIGS. 3A-3B are schematic diagrams of eye tracking devices havingdifferent configured light sources in accordance with various aspects ofthe present disclosure.

FIG. 4 is a flow diagram of an example method of eye tracking inaccordance with various aspects of the present disclosure.

FIG. 5 is a block diagram depicting an example system for eye trackingin accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

Although the following detailed description contains many specificdetails for the purposes of illustration, anyone of ordinary skill inthe art will appreciate that many variations and alterations to thefollowing details are within the scope of the invention. Accordingly,the exemplary embodiments of the invention described below are set forthwithout any loss of generality to, and without imposing limitationsupon, the claimed invention.

Introduction

Eye tracking devices may utilize a lighting apparatus to illuminateeyes, and a sensor to detect the illuminated eyes. The eye tracking datagathered by the sensor may then be analyzed to determine the desired eyegaze characteristics, such as eye position, eye movements, gazedirection, gaze point, and the like. It would be desirable for an eyetracking device to be able illuminate eyes in a wide variety ofpositions with respect to the tracking device. Unfortunately, providinga wide area of illumination with an eye tracking device usingtraditional techniques would prove inefficient and consume a significantamount of power.

Implementations of the present disclosure may overcome these and otherdrawbacks by providing a wide area of illumination using a trackingdevice which as a plurality of light sources oriented to emit light atdifferent angles. Each differently oriented light source may illuminatean additional area so that the tracking device may illuminate one ormore users in a wide variety of positions with respect to the trackingdevice. Furthermore, these light sources may be selectively turned offbased on which light sources are providing the illumination of the user.In yet further aspects, the position of the user may be tracked inreal-time so that the light sources may be dynamically turned on and offbased upon present user position.

These and further aspects of the present disclosure will be apparentupon consideration of the following detailed description of variousimplementation details and their accompanying drawings.

Implementation Details

An illustrative example of a system for eye tracking is depicted inFIG. 1. The example system 100 includes an eye tracking device 102 whichhas a wide-angle lighting apparatus 110 and a sensor 112 that issensitive to light emitted from the lighting apparatus 110. In theimplementation depicted in FIG. 1, the wide-angle lighting apparatus 110has a plurality of individual light sources, each of which may beoriented to emit light in a different direction. Each of the lightsources may emit a cone of illumination 131, and each of theillumination cones 131 may be projected outward in a different directionto cover a different area of the operating environment so that the conesare collectively capable of illuminating a wide area. Depending on thenature of the lighting apparatus 110 some of the illumination cones mayat least partially overlap with each other.

One or more sensors 112 of the eye tracking device 102 may be configuredto detect light reflected from an area encompassed by the illuminationcones 131 in order to detect the eyes of a user 106 whose eyes areilluminated by the lighting apparatus 110. As shown in FIG. 1, the user106 may occupy a wide variety of positions relative to the trackingdevice 102 and still have eyes illuminated by the lighting apparatus 110for eye tracking purposes, due to the wide area encompassed by theillumination cones 131. The example system 100 may also include adisplay device (not pictured) which may operate in coordination with theeye tracking device 102 for various eye tracking applications, e.g., todetermine a user's gaze point on the screen.

In one example, the wide angle lighting apparatus 110 of the eyetracking device 102 may include a plurality of light sources, e.g., inthe form of light-emitting diodes (LEDs), such as infrared LEDs whichactively emit visible or non-visible light, and each of the LEDs may befixed to a casing of the eye tracking device 102 (or lighting apparatus110) in a different relative orientation. By way of example, the sensor112 may be a camera, such as an infrared camera, which may also be fixedto the casing of the eye tracking device 102 in an orientation thatfacilitates image capture of some or all of the area encompassed by thecones of illumination 131.

In the illustrative example depicted in FIG. 1, the eye tracking device102 may be used to gather eye tracking data by emitting light from thewide-angle lighting apparatus 110 to illuminate the eyes of a user 106,and detecting reflections of the emitted light with the sensor 112. Thesensor data may be analyzed to determine one or more gazecharacteristics of the user, such as eye position, eye movements, gazedirection, gaze point, and the like, based on eye illuminationscontained in the sensor data. For example, this may involve analyzingthe images captured with the sensor 112 to identify eye illuminations,including corneal reflections caused by the emitted light and/or one ormore Dark Pupils (i.e. a dark spot at a pupil location of an eyeilluminated by light that is off-axis from the camera 112). Thesecharacteristic eye illuminations in the images may be analyzed todetermine the desired gaze characteristics using a computing deviceconfigured to process the images in accordance with eye tracking imageprocessing algorithms.

In the example depicted in FIG. 1, each of the cones 131 may benon-overlapping or substantially non-overlapping so as to minimize theamount of light sources needed to illuminate a user 106 at any giventime, thereby conserving power. However, it will be appreciated thatcones having some overlap may also be used in other implementations, inwhich case two or more light sources may be illuminating a user at anygiven time.

FIGS. 2A-2D depict an example process flow of an eye tracking techniqueusing a system 200 similar to the system 100 depicted in FIG. 1.

As shown in FIG. 2A, an eye tracking technique may include emittinglight from a wide angle lighting apparatus 210 in order to illuminatethe eyes of a user 206. The wide angle lighting apparatus 210 mayinclude a plurality of light sources oriented in different directions,and each of the light sources may produce a cone of illumination 231.

As illustrated in FIG. 2A, the eye tracking technique may involveinitially illuminating an area using all (or most) of the light sourcesof the wide angle lighting apparatus 210 so that a wide area isinitially illuminated. The area illuminated by the lighting apparatus210 may be detected by a sensor 212 of the eye tracking device 202,e.g., by capturing images of an area illuminated by the lightingapparatus 210. As a result of the wide area of illumination provided bythe plurality of light sources, a user's eyes located anywhere withinthe cones of illumination 231 may be illuminated and tracked with theeye tracking device 202, giving the system flexibility for a widevariety of system setups and adaptability to a wide variety of userpositions.

After initially illuminating the area using all or most of the lightsources of the wide angle lighting apparatus 210, the system 200 maythen selectively turn off one or more of the initially illuminated lightsources while selectively leaving on or more of the initiallyilluminated light sources. As shown in FIG. 2B, light sources that arenot contributing to illumination of the user can be turned off, e.g., toconserve power, while the one or more light sources 233 that docontribute to illumination of the user 206 may selectively stay on.

In one implementation, this may be accomplished by analyzing the datagathered with the sensor 212 to determine which of the light sources iscontributing to the illumination of the user's eyes. For example, thesensor 212 may capture infrared images of the user 206 and analyze theimages in order to determine which of the light sources are contributingto the illumination of the user's eyes and providing useful eyeilluminations for the data gathered with the sensor 212. By way ofexample, this analysis may be accomplished by identifying one or moreusers within the images, e.g., using facial recognition or recognitionof the characteristic eye illuminations to identify a presence ofilluminated eyes, and estimating a relative location of the identifieduser with respect to the eye tracking device 202. The user's locationwithin the images may then be correlated with a known relativeorientation of the light sources with respect to the camera 212 in orderto determine of which of the light sources corresponds with the user'slocation within the image. These light sources may be identified as oneor more “contributing light sources” for the eye tracking system so thatthey can be kept on to illuminate the user 206 while tracking the userseyes, and the remaining light sources may be turned off, as depicted inFIG. 2B.

In another example, the contributing light sources 233 may be identifiedusing some other known information about the tracking device 202 and itslighting apparatus 210. For example, each of the light sources may bepulsed on and off at a different known pulse frequencies. Imagescaptured during the pulsing of the light may be analyzed to detect apresence of reflections of sufficient intensity at one or more of theseknown frequencies and/or a presence of reflections at an identifiedlocation of a user at one or more of the known pulse frequencies. Iflight in the emitted wavelength/wavelength range at any of thesefrequencies are present in the images, the frequency may be correlatedto the known frequencies of the individual light sources to determinewhich of the light sources should be identified as a contributing lightsource 233. Alternatively, each of the lighting apparatus 210 mayinclude a plurality of light sources that emit light of differentcorresponding frequencies, e.g., a different infrared frequency for eachlight source. The tracking device may include a camera that candistinguish these different frequencies and produce correspondingimages. Images captured with the camera may be analyzed to detect apresence of reflections of sufficient intensity at one or more of theseknown frequencies at an identified location of a user. By correlatingthe frequencies of light illuminating the user's face in the image tothe corresponding known frequencies emitted by the light sources of thelighting apparatus 210 may determine which of the light sources shouldbe identified as a contributing light source 233.

Turning to FIGS. 2C-2D, the system 200 may be configured to dynamicallyadjust in real-time which light sources are currently used emit light233, e.g., to account for changes in position of the user 206. Forexample, as shown in FIG. 2C, the user has changed positions withrespect to the tracking device, affecting the illumination provided bythe previously identified contributing light source of FIG. 2B. Thesystem 200 may react, e.g., on the fly, by turning on one or more of theother light sources to sufficiently illuminate the user's eyes for theeye tracking device 202.

In the situation depicted in FIG. 2C, it may desirable to keep more thanone of the light sources on in order to properly illuminate the user'seyes, due to the user's position at a border (or region of overlap)between two or more of the cones of illumination 233 provided by thecontributing light sources.

As shown in FIG. 2D, the system may continue to adjust to the user'scurrently position by turning off the previous contributing lightsources in order to further conserve power based on the user's currentposition.

It is noted that the system 200 may be configured to adjust dynamicallyto the present location of the user in a variety of ways.

In one implementation, the system may be configured to continuously orperiodically analyze data gathered with the eye tracking device 202 inorder to detect changes relevant to the user's position and relevant tothe sufficiency of the illumination provided by the currently on lightsource(s) 233.

For example, the system 200 may detect that the illumination beingcurrently provided is insufficient based on a decrease in the system'sability to track eyes and/or gather data containing eye illuminations,or by the eye tracking cutting out. Upon a determination that theillumination being provided by the currently illuminated light source(s)is no longer sufficient, the system may, in one example, turn on all ofthe light sources and repeat a process similar to the initial processdescribed above with respect to FIGS. 2A-2B in order to re-identify thecurrently contributing light source. In another example, the system 200may instead turn on only one or more of the light sources which areadjacent to the previously identified contributing light sources,because the insufficiency may be due to a small movement outside of theillumination cone of the previously contributing light sources and intoa cone corresponding to one of the adjacent light sources.

By way of further example, the system may analyze the sensor data todetermine which light sources should be turned on in order to accountfor the user's movement. For example, as the user 206 moves around, theimages of the user may be analyzed to determine the user's relativemovement with respect to the tracking device, including the lightsources, and the user's movement may be correlated with correspondingLEDs of the dynamic lighting apparatus 210. As a simple example, ifanalysis of one or more images captured with the sensor 212 indicatesthat the user 206 is moving in a leftward direction with respect to thetracking device 202, the system may be configured to turn a light sourceadjacent to the currently on light source in a leftward orientationrelative to the presently on light source.

In yet another example, an additional sensor may be included with theeye tracking device to identify a relative location of one or more usersto the eye tracking device 202.

In yet other implementations, a conventional lighting control techniqueto the system of 200 in order to provide illumination of the eyes of theuser 206.

It is noted that the differently oriented light sources may be fixed indifferent orientations in order to avoid a need for some complexmechanical or other optical system for providing illumination of a widepossibility of angles, thereby providing a relatively reliable,efficient, and low cost solution. Any of a variety of differentgeometric configurations and techniques may be used so that a pluralityof light sources emit light in different directions.

For example, in the implementations depicted in FIGS. 1 and 2, each ofthe different light sources of the wide angle lighting apparatus 110,210 may be fixed in a different orientation with respect to a casing ofthe eye tracking device, and it will be appreciated that a variety ofdifferent configurations may be used.

By way of example, and not by way of limitation, one possibleimplementation of a wide angle lighting apparatus 310 a is depicted inFIG. 3A. The example lighting apparatus 310 a has a plurality ofindividual light sources 335, each of which is fixed in a differentrelative orientation. In the example depicted in FIG. 3A, eachindividual light source 335 may be an infrared LED, and the LEDs may befixed to a casing component 337 having a convex surface. Each LED 335may be disposed in an orientation that is normal to the convex surfaceof the casing component 337 at a different location, resulting in eachof the discrete light sources 335 emitting light 339 outward in adifferent direction.

By way of further non-limiting example, another wide angle lightingapparatus 310 b is depicted in FIG. 3B. In the example depicted in FIG.3B, light sources 335 are configured to emit light 339 in the samedirections depicted in the example of FIG. 3A, but the light sources arefixed in a planar or substantially planar configuration, rather thanbeing fixed to a convex surface. In one example, the casing component337 of FIG. 3B may be a horizontal bar.

It is noted that a wide variety of geometric configurations arepossible. For example, the individual light sources may be configured tocover a horizontal area, such as by being oriented in differenthorizontal directions (i.e. horizontal with respect to the ground). Inyet further examples, the individual light sources may be configured tocover a wide vertical area, such as wide vertical direction (i.e.vertical with respect to the ground). In yet further examples, the lightsources may be configured to cover a wide area in both horizontal andvertical directions using light sources oriented in both differenthorizontal angles and different vertical angles, such as by beingdisposed on a surface of a spherical casing component with each emittinglight at an outward direction normal to the surface.

It is further noted that the lighting apparatus may include one or morelight sources configured to emit light in the same orientation, so longas there is a plurality of light sources which each emit light atdifferent orientations.

FIG. 4 illustrates a flow diagram depicting an example eye trackingmethod 400 in accordance with various aspects of the present disclosure.By way of example, some or all of the method 400 may be performed by acomputing device coupled which is configured to receive data from asensor of an eye tracking device and/or send control outputs to alighting apparatus of the eye tracking device, and the method 400 mayhave similarities to the method depicted in FIGS. 2A-2D.

The method 400 may involve initially emitting light from all lightsources of a plurality of light sources of an eye tracking device. Thismay include, e.g., turning on all of the light sources 451 of an eyetracking device which has a plurality of light sources, each of whichmay be oriented to emit light in a different direction. For example, thelighting apparatus may be similar to the lighting apparatus 210 of FIG.2A, and the lights may emit cones of illumination which a wide area asdepicted in FIG. 2A. It is noted that the system may be configured toinitially emit light automatically from all of the light sources, e.g.,when powered on by a user, or a computing device may be configured toturn on the lights by sending a control signal which powers on all ofthe lights.

An area illuminated by emitted light may then be detected with a sensorof the eye tracking device. This may involve capturing images 453 of anarea illuminated by the wide angle lighting apparatus of the eyetracking device using a camera that is sensitive to the light emittedfrom the lighting apparatus. By way of example, and not by way oflimitation, the emitted light may be infrared light, and the imagescaptured may be infrared images captured with an infrared sensitivecamera of the eye tracking device.

The eye tracking data gathered from the detection of the illuminatedarea may be analyzed to determine which light sources may be providinguseful light for eye tracking purposes and which of the light sourcesare not. The data may be analyzed to identify one or more of the lightsources 455 as “contributing light sources” in which case the remaininglight sources may be designated “non-contributing light sources.” A userwhose eyes are being tracked may be positioned in only one or more ofthe cones of illumination provided by the light sources, e.g., as shownin FIG. 2B, and one or more light sources providing the cone or cones ofillumination in which the user is located may be identified fromcorrespondence between the eye tracking data and known orientations ofthe light sources. For example, images gathered with the eye trackingdevice may be analyzed to determine a relative location of illuminatedeyes within the images (e.g. using facial recognition techniques orrecognition of eye illuminations contained in the images). The relativelocation of the user/user's eyes within the images may be correlated toa known orientation of one or more of the light sources in order todetermine which of the light sources are contributing to eyeilluminations used for eye tracking.

The method 400 may then involve turning off one or more of the lightsources 457 not identified as contributing light sources. For example, acomputing device performing the analysis of the images may send acontrol output to the eye tracking device which causes the selectedlight sources to be turned off, such as shown in FIGS. 2A-2B. Afterturning off the non-contributing light sources 457, the sensor data maycontinue to be analyzed in order to track one or more eyes bydetermining gaze characteristics from analysis of the eye illuminations459 caused by emitting light from the identified contributing lightsource. By way of example, this may involve analyzing one or moreinfrared images to determine one or more gaze characteristics, such aseye position, eye movements, gaze direction, gaze point, or acombination thereof, using a Dark Pupil or Bright Pupil trackingalgorithm executed by the computing device. The method 400 may outputone or more gaze characteristics 461, e.g., for a computer applicationincorporating eye tracking features, from the analysis of theilluminated eyes.

The method 400 may also involve dynamically adjusting a currently onlight source in real-time, e.g. as shown and described above in FIGS.2C-2D and accompanying disclosure. By way of example, this may involvecontinuously or periodically determining whether or not the illuminationprovided by the current light source is sufficient 463 to illuminate theeyes being tracked. For example, if the eye illuminations in the sensordata weak or cut out, or if user motion is detected from analysis of theimages, it may be determined that the current illumination is notsufficient and that the lighting apparatus should be adjusted. This mayinvolve turning on some or all of the other light sources, i.e. thepreviously turned off light sources, as described above with respect toFIGS. 2A-2D. In the example illustrated in FIG. 4, all of the lightsources are turned on again, and the initial process used to identifythe contributing light source is repeated; however, but it is understoodthat other variations are possible.

FIG. 5 depicts an example system for eye tracking 500 to furtherillustrate various aspects of the present disclosure. The example system500 may include a computing device 560 which is coupled to an eyetracking device 502 and a display device 504 in order to perform eyegaze tracking and/or calibration for eye tracking in accordance withaspects of the present disclosure.

The display device 586 may be in the form of a cathode ray tube (CRT),flat panel screen, touch screen, or other device that displays text,numerals, graphical symbols, or other visual objects. According toaspects of the present disclosure, the computing device 560 may be anembedded system, mobile phone, personal computer, tablet computer,portable game device, workstation, game console, and the like. Moreover,the computing device 560, the eye tracking device 502, the displaydevice 504, or any combination thereof may form an integral unit or beimplemented as separate components which may be in communication witheach other.

The eye tracking device 502 may be coupled to the computing device 560,and may include a wide angle lighting apparatus 510, which may besimilar to lighting apparatus 210 of FIGS. 2A-2D. By way of example, andnot by way of limitation, the lighting apparatus 510 may be in the formof a plurality of infrared LEDs 535, each of which may be electronicallycontrollable by the computing device 560 to turn on and off, e.g. asdescribed above with respect to FIG. 4, and which may be configured toilluminate a user's eyes in order to gather eye tracking data with thesensor 512. The sensor 512 of the eye tracking device may be a detectorwhich is sensitive to light emitted from the lighting apparatus 510. Forexample, the sensor 512 may be a camera sensitive to the light sourcesuch as an infrared camera, and the camera 512 may be positionedrelative to the eye tracking device and the lighting apparatus so thatit may capture images of an area illuminated by the lighting apparatus510.

The computing device 560 may be configured to operate in coordinationwith the eye tracking device 502 and the display device 504, in order toperform eye gaze tracking and determine lighting conditions inaccordance with aspects of the present disclosure. The computing device560 may include one or more processor units 570, which may be configuredaccording to well-known architectures, such as, e.g., single-core,dual-core, quad-core, multi-core, processor-coprocessor, cell processor,and the like. The computing device 560 may also include one or morememory units 572 (e.g., RAM, DRAM, ROM, and the like).

The processor unit 570 may execute one or more programs, portions ofwhich may be stored in the memory 572, and the processor 570 may beoperatively coupled to the memory 572, e.g., by accessing the memory viaa data bus 576. The programs may be configured to perform eye gazetracking and determine lighting conditions for the system 500. By way ofexample, and not by way of limitation, the programs may include wideangle light gaze tracking programs 574, execution of which may cause thesystem 500 to perform a method having one or more features in commonwith the method 400 of FIG. 4. By way of example, and not by way oflimitation, the gaze tracking programs 574 may include processorexecutable instructions which cause the system 500 to determine one ormore gaze tracking characteristics from eye tracking data gathered withthe camera 512 while light is emitted from the lighting apparatus 510.The gaze tracking programs 574 may also include instructions whichanalyze images gathered with the camera 512 in order to determine whichlight source out of the plurality of light sources 535 is currentlycontributing to eye illuminations, e.g., as described above with respectto FIG. 4.

The computing device 560 may also include well-known support circuits578, such as input/output (I/O) circuits 579, power supplies (P/S) 580,a clock (CLK) 581, and cache 582, which may communicate with othercomponents of the system, e.g., via the bus 576. The computing device560 may also include a mass storage device 584 such as a disk drive,CD-ROM drive, tape drive, flash memory, or the like, and the massstorage device 584 may store programs and/or data. The computing device560 may also include a user interface 588 to facilitate interactionbetween the system 500 and a user. The user interface 588 may include akeyboard, mouse, light pen, game control pad, touch interface, or otherdevice.

The input/output components 579 may also include a controller whichinterfaces with the eye tracking device 502 in order to control the ofthe lighting apparatus 510, e.g. based on the image analysis of the gazetracking programs 574. The system 500 may also execute one or moregeneral computer applications (not pictured), such as a video game,which may incorporate aspects of eye gaze tracking as sensed by thetracking device 502 and processed by the tracking programs 574.

The computing device 560 may include a network interface 590, configuredto enable the use of Wi-Fi, an Ethernet port, or other communicationmethods. The network interface 590 may incorporate suitable hardware,software, firmware or some combination thereof to facilitatecommunication via a telecommunications network. The network interface590 may be configured to implement wired or wireless communication overlocal area networks and wide area networks such as the Internet. Thecomputing device 560 may send and receive data and/or requests for filesvia one or more data packets 599 over a network.

It will readily be appreciated that variations on the componentsdepicted in FIG. 5 are possible, and that various ones of thesecomponents may be implemented in hardware, software, firmware, or somecombination thereof. For example, the some features or all features ofthe calibration programs contained in the memory 572 and executed by theprocessor 570 may instead be implemented via suitably configuredhardware, such as one or more application specific integrated circuits(ASIC) configured to perform some or all of a method in accordance withaspects of the present disclosure, such as method 400 of FIG. 4.

Conclusion

It is noted that aspects of the present disclosure have been describedwith reference to eye tracking devices that use infrared light sources,which has developed as a relatively standard light source for opticaleye tracking techniques. However, it is understood that otherimplementations are possible. For example, in implementations of thepresent disclosure, other invisible light sources are possible, such asultraviolet light. By way of further example, in implementations of thepresent disclosure, visible light sources are possible for eyeillumination, although it may be desirable to use invisible lightsources in order to avoid distracting a user.

It is further noted that aspects of the present disclosure have beendescribed with reference to tracking the eye or eyes of a single user.However, it is understood that other implementations are possible, suchas tracking the eyes of more than one user, and the technique can beadapted to account from differently positioned users simultaneously byemitting light outward at a plurality of different directions from aplurality of differently oriented light sources from the plurality oflight sources.

While the above is a complete description of the preferred embodiment ofthe present invention, it is possible to use various alternatives,modifications and equivalents. Therefore, the scope of the presentinvention should be determined not with reference to the abovedescription but should, instead, be determined with reference to theappended claims, along with their full scope of equivalents. Any featuredescribed herein, whether preferred or not, may be combined with anyother feature described herein, whether preferred or not. In the claimsthat follow, the indefinite article “a”, or “an” refers to a quantity ofone or more of the item following the article, except where expresslystated otherwise. The appended claims are not to be interpreted asincluding means-plus-function limitations, unless such a limitation isexplicitly recited in a given claim using the phrase “means for.”

What is claimed is:
 1. a) emitting light from an eye tracking device,wherein said emitting the light includes initially emitting the lightfrom all light sources of a plurality of light sources of the eyetracking device, each said light source of the plurality being orientedto emit light at a different angle; b) detecting an area illuminated bythe light with a sensor of the eye tracking device; identifying one ormore of the light sources of the plurality as contributing light sourcesfrom analysis of data gathered from said detecting the area, saididentifying the light sources as the contributing light sources beingbased on a determination that the contributing light sources illuminateone or more eyes, wherein identifying one or more of the lights sourcesof the plurality as contributing light sources comprises pulsing one ormore of the plurality at a different pulse frequency than a pulsefrequency of the rest of the light sources of the plurality anddetecting the presence of reflections at the different pulse frequencyor the pulse frequency of the rest of the light sources of theplurality; c) turning off one or more light sources of the plurality notidentified as the contributing light sources while emitting the lightfrom the contributing light sources; and subsequently repeating a), b),and c) one or more times.
 2. The method of claim 1, wherein the sensoris a camera, wherein the data is one or more images, and wherein saiddetecting the area includes capturing the images with the camera.
 3. Themethod of claim 1, wherein the sensor is a camera, wherein the data isone or more images, wherein said detecting the area includes capturingthe images with the camera, and wherein said identifying thecontributing light sources includes identifying a location of one ormore illuminated eyes within the images and identifying the contributinglight sources based on correspondence between the location and knownorientations of each said light source.
 4. The method of claim 1,wherein the sensor is a camera, wherein the data is one or more images,wherein said detecting the area includes capturing the images with thecamera, and wherein the method further comprises, after said turning offthe light sources, analyzing the images to determine one or more gazecharacteristics of the one or more eyes illuminated by said emitting thelight.
 5. The method of claim 1, wherein each said light source is aninfrared LED, wherein the sensor is an infrared camera, wherein the datais one or more infrared images, and wherein said detecting the areaincludes capturing the infrared images with the infrared camera.
 6. Themethod of claim 1, wherein said turning off the light sources includessending a control signal to the eye tracking device which causes saidturning off of the light sources.
 7. A system comprising: an eyetracking device having a sensor and a plurality of light sources, eachsaid light source being oriented to emit light at a different angle; anda computing device, wherein the system is configured to perform amethod, the method comprising: a) emitting light from the eye trackingdevice, wherein said emitting the light includes initially emitting thelight from all light sources of the plurality of light sources; b)detecting an area illuminated by the light with the sensor; c)identifying, with the computing device, one or more of the light sourcesof the plurality as contributing light sources from analysis of datagathered from said detecting the area, said identifying the lightsources of the plurality as the contributing light sources being basedon a determination that the contributing light sources illuminate one ormore eyes, wherein identifying one or more of the lights sources of theplurality as contributing light sources comprises pulsing one or more ofthe plurality at a different pulse frequency than a pulse frequency ofthe rest of the light sources of the plurality and detecting thepresence of reflections at the different pulse frequency or the pulsefrequency of the rest of the light sources of the plurality; d) turningoff one or more light sources of the plurality not identified as thecontributing light sources while emitting the light from thecontributing light sources; and subsequently repeating a), b), c) and d)one or more times.
 8. The system of claim 7, wherein each said lightsource is an infrared LED.
 9. The system of claim 7, wherein each saidlight source is an infrared LED, wherein each said infrared LED is fixedto a casing of the eye tracking device at a different angle, whereineach infrared LED is configured to emit light in a differentnon-overlapping region in front of the eye tracking device.
 10. Thesystem of claim 7, wherein the sensor is a camera, wherein the data isone or more images, and wherein said detecting the area includescapturing the images with the camera.
 11. The system of claim 7, whereinthe sensor is a camera, wherein the data is one or more images, whereinsaid detecting the area includes capturing the images with the camera,and wherein said identifying the contributing light sources includesidentifying a location of one or more illuminated eyes within the imagesand identifying the contributing light sources based on correspondencebetween the location and known orientations of each said light source.12. The system of claim 7, wherein the sensor is a camera, wherein thedata is one or more images, wherein said detecting the area includescapturing the images with the camera, and wherein the method furthercomprises, after said turning off the light sources, analyzing theimages to determine one or more gaze characteristics of the one or moreeyes illuminated by said emitting the light.
 13. The system of claim 7,wherein each said light source is an infrared LED, wherein the sensor isan infrared camera, wherein the data is one or more infrared images, andwherein said detecting the area includes capturing the infrared imageswith the infrared camera.
 14. The system of claim 7, wherein saidturning off the light sources includes sending a control signal from thecomputing device to the eye tracking device which causes said turningoff of the light sources.
 15. A non-transitory computer readable mediumhaving processor-executable instructions embodied therein, whereinexecution of the instructions by a processor causes the processor toperform a method, the method comprising: a) emitting light from an eyetracking device, wherein said emitting the light includes initiallyemitting the light from all light sources of a plurality of lightsources of the eye tracking device, each said light source beingoriented to emit light at a different angle; b) detecting an areailluminated by the light with a sensor of the eye tracking device;identifying one or more of the light sources of the plurality ascontributing light sources from analysis of data gathered from saiddetecting the area, said identifying the one or more light sources ofthe plurality as the contributing light sources being based on adetermination that the contributing light sources illuminate one or moreeyes, wherein identifying one or more of the lights sources of theplurality as contributing light sources comprises pulsing one or more ofthe plurality at a different pulse frequency than a pulse frequency ofthe rest of the light sources of the plurality and detecting thepresence of reflections at the different pulse frequency or the pulsefrequency of the rest of the light sources of the plurality; c) turningoff one or more light sources of the plurality not identified as thecontributing light sources while emitting the light from thecontributing light sources; and subsequently repeating a), b), and c)one or more times.
 16. The non-transitory computer readable medium ofclaim 15, wherein the sensor is a camera, wherein the data is one ormore images, and wherein said detecting the area includes capturing theimages with the camera.
 17. The non-transitory computer readable mediumof claim 15, wherein the sensor is a camera, wherein the data is one ormore images, wherein said detecting the area includes capturing theimages with the camera, and wherein said identifying the contributinglight sources includes identifying a location of one or more illuminatedeyes within the images and identifying the contributing light sourcesbased on correspondence between the location and known orientations ofeach said light source.
 18. The non-transitory computer readable mediumof claim 15, wherein the sensor is a camera, wherein the data is one ormore images, wherein said detecting the area includes capturing theimages with the camera, and wherein the method further comprises, aftersaid turning off the light sources, analyzing the images to determineone or more gaze characteristics of the one or more eyes illuminated bysaid emitting the light.
 19. The non-transitory computer readable mediumof claim 15, wherein each said light source is an infrared LED, whereinthe sensor is an infrared camera, wherein the data is one or moreinfrared images, and wherein said detecting the area includes capturingthe infrared images with the infrared camera.
 20. The non-transitorycomputer readable medium of claim 15, wherein said turning off the lightsources includes sending a control signal to the eye tracking devicewhich causes said turning off of the light sources.